Field of the Invention
The present invention relates to a liquid crystal display panel, and particularly, to a liquid crystal display panel based on a twisted nematic (TN) mode and a liquid crystal display (LCD) apparatus.
Discussion of the Related Art
Touch panels are a type of input device that is included in display apparatuses, such as liquid crystal display (LCD) apparatuses, field emission displays (FEDs), plasma display panels (PDPs), electrophoretic displays (EPDs), and electrophoretic displays (EPDs), and enables a user to input information by directly touching a screen with a finger, a pen or the like while looking at the screen of the display device.
A method of manufacturing an LCD apparatus including a touch panel includes an add-on type, where a panel displaying an image and a touch panel that determines whether there is a touch are separately manufactured and bonded to each other, and an in-cell type where the touch panel is built into the panel displaying an image.
A liquid crystal display panel configuring an LCD apparatus among the display apparatuses may be implemented in a TN mode or an in-plane switching (IPS) mode.
Particularly, in a liquid crystal display panel using the TN mode, liquid crystal that is aligned to be twisted between an upper substrate and a lower substrate is controlled by a vertical electric field generated between the upper substrate and the lower substrate, and thus, the amount of light passing through the liquid crystal is controlled. In this instance, a switching transistor and a pixel electrode are disposed on the lower substrate of the liquid crystal display panel, and a black matrix, a color filter, an overcoating layer, a common electrode, and a column spacer are disposed on the upper substrate of the liquid crystal display panel.
In a liquid crystal display panel to which the in-cell type and the IPS mode are applied, a plurality of touch electrodes are disposed on the lower substrate.
However, in the liquid crystal display panel using the TN mode, it is difficult for the touch electrodes to be disposed on the lower substrate on which the switching transistor and the pixel electrode are disposed.
For example, when a user touches the upper substrate of the liquid crystal display panel using the TN mode where the touch electrodes are disposed on the lower substrate, an electric field generated based on a touch driving signal applied to the touch electrodes disposed on the lower substrate is cut off by the common electrode disposed on the upper substrate.
For this reason, it is difficult to implement the liquid crystal display panel using the TN mode and the in-cell type where the touch panel is included in the lower substrate.